Radio static-eliminating apparatus



y 2, 1929- i c. H. SEYMOUR 1.719.087

RADIOSTATIC ELIMINATING APPARATUS Filed July 5, 11927 ATITORNE Patented July 2, 1929.

UNITED STATES CHARLES H. SEYMOUR, OF KANSAS CITY, MISSOURI.

RADIO STATIGELIMINATING APPARATUS.

Application filed July 5, 1927. Serial No. 203,413.

My invention relates to improvements in radio static eliminating apparatus.

()ne of the objects of my invention is to provide a novel apparatus with the use of which in connection with a radio receiving set a large amount oi. the static will be eliminated without appreciably reducing the volume or interfering with the clearness of the received radio signal waves.

ll. further object ,Oif my invention is to provide an apparatus of the kind described, which is very simple, cheap, durable, not likely to get out of order, and which may be readily installed with ease in most any of the usual types of radio receiving sets.

The novel features oi" my invention are hereinafter fully described. and claimed.

Tn the accompanying drawing, which illustrates the preferred embodiment of my invention,

Fig. 1 is a plan view of my improved apparatus.

Fig. 2 is a diagrammatic view of an electrical circuit which includes a radio receiving set, an aerial. and my improved apparatus all in. series with each other and the ground.

Similar reference characters designate similar parts in the different views.

My improved apparatus is provided with a base 11 having mounted thereon an. induction coil 2, Fig. 1, having a primary winding 3, a secondary winding 1 and a non magnetic conductive core 5, preferably a stick oi carbon.

On the base are mounted. four binding,

posts 6, 7, 8 and. 9.

The ends of the winding 3 are respectively connected to the posts 6 and 7, and the ends oi the winding l are respectively electrically connected to the binding posts 8 and 9.

Two grid leaks 10 and 11 are respectively electrically connected in multiple with the windings 3 and. 4 through the posts 6 and 7 and 8 and 9. The grid leak 11 preferably has a lower leak resistance than the grid leak 10 which is in multiple with the primary winding 3, the grid leaks being respectively of resistances of 1 megohm and 5 megohms.

In connecting with an. aerial and a receiving set, the aerial conductor 12 is connected to the post 6,

A conductor 13 connects the post 7 with an antenna binding post 14 of a receiving set 15, of usual type. The ground binding post 16 elf the set is connected by a conductor 17 to the binding post 9, and the binding post 8 is connected to ground by a conductor 18.

The windings 3 and {L are thus connected in series with each other and with the aerial conductor and the receiving set to ground. lVhen the radio waves are received by the aerial, the waves and static will enter the apparatus by the aerial conductor 19 and will be carried thereby to the post 6 where the flow will be divided, some passing through the winding 3 to the post 7, and

some passing through the grid leak 10 to the post 7, thence through the conductor 13 to the antenna binding post 1 1, thence through the set to the post 16, and thence by the conductor 17 to the binding post 9, thence dividing by way of the winding 1 and grid leak 11 to the post 8, and thence to ground by the conductor '18.

In passing through the apparatus, the static is to a very great extent eliminated without appreciably reducing the volume or interfering with the clearness of the radio signals. This efleet is effected in some manner by the presence in the induction coil of the carbon core, as with tests which I have made, the effect is not obtained with a cell having a magnetic core, or with one not conductive, nor when no core is used in the coil.

The grid leaks are also essential to successful use, as ordinary fixed condensers will not effect the result.

I have no established theory as to the principle involved.

lVith induction coils with which I have had the best results, the windings 3 and 4: were of like gage of wire, and like numbers of turns, and cotton covered with no other insulation between the prii'nary winding and the carbon core. With silk covered wire or with cotton covered and an insulation wrapping between the primary winding and the carbon the elimination was not etl ected to anything like the same extent as with the cotton covered winding wound directly upon the carbon stick.

Also the best results were obtained with the greater resistance grid leak in multiple with the primary winding.

lVhile I have obtained the greatest reduction in static with the use of the grid leaks 10 and 11 in the manner described, the greater portion of static in the reception will be eliminated without the employment of the grid leaks, providing that the induction coil is provided with the carbon core. The reception, however, is improved with the use of the grid leaks as set forth.

I do not limit my invention to the structure shown and described, as many modifications, within the scope of the appended claims, may be made without departing from the spirit of my invention.

What I claim is 1. In a radio static eliminating apparatus, an induction coil having a primary winding, a secondary winding and acarbon core, the ends of the primary winding being adapted for electrical connection respectively to an aerial and to the antenna binding post of a radio receiving set, the ends of the secondary winding being adapted forelectrical connection respectively with the ground and to the ground binding post of said set, and two grid leak condensers respectively electrically connected in multiple with said windings.

2. In a radio static eliminating apparatus, the combination with an aerial conductor and a radio receiving set, of an induction coil having a primary winding, a secondary winding and a carbon core, two grid leak condensers respectively connected in multiple with said windings, and means electrically connecting said aerial, said windings, and said set in series with each other and the ground.

3. In a radio static eliminating apparatus, the combination with an aerial conductor and a radio receiving set, of an induction coil having a primary winding, a secondary winding and a carbon core, and means cloctrically connecting in series with each other and the ground said conductor, said windings and said set.

In testimony whereof I have signed my name to this specification.

CHARLES H. SEYMOUR. 

